# Flashcard Set Preview

Side ASide B

A descriptive measure of a sample

statistic

method of organizing, summarizing, and presenting data

descriptive statistics

The group of all items of interest

population

the process of making an estimate. prediction, or decision about a population based on sample data

statistical inference

a set of data drawn from a population

sample

the data can be arranged in order & differences b/w data values are meaningful

interval scale

the data consists of names, labels, or categories. There are no criteria for ordering the data from smallest to largest

nominal scale

the data can be arranged in order & both & ratios b/w data values are meaningful. Also data has a true, absolute zero.

ratio scale

the data can be arranged in order. However, differences b/w data values either can;t be determined or are meaningless

ordinal scale

The Requirements of a Random Sample

1. Each indiv. in population of interest must have an equal probability of being of being included in the sample 2. They all have equal chance of being picked

Divide the entire population into pre-existing segments or clusters. The clusters are often geographic. Make a random selection of clusters. Include every member of each selected cluster...

Cluster sampling

Create a sample by using data from population members that are readily available.

Convenience Sampling

A simple random sample of

*n*measurements from a population is a subset of the population selected in a manner such that every sample of size*n*from the population has...
Simple Random Sampling

Divide the entire population into distinct subgroups called strata. The strata are based on a specific characteristic such as age, income, education level, and so on. All members of...

Stratified Sample

Number all members of the population sequentially. Then, from a starting point selected at random, include every

*k*th member of the population in the sample.
Systematic sampling

A variable that describes an individual by placing the individual into a category or group, such as male or female.

Qualitative variable

A quantitative variable has a value or numerical measurement for which operations such as addition or averaging make sense.

Quantitative variable

numerical measure that describes an aspect of a population.

Parameter

Given a random sample of 9 skiers at Vail:18, 25, 32,16, 41, 52, 29, 58, 23Give the 5 number summary values w labelsX=

XMin= 16; Q1= 20.5; Med (Q2)= 29; Q3= 46.5; Xmax=58 Age of skiers

What is IQR and how do you find it?

Interquartile RangeQ3-Q1= 20.5

How do you find the sample mean?

Summation of X divided by n

How do you find the median?

Order the data and then find the physical middle; Position= (n+1)/2

How do you find the mode?

it is the most frequent

How to find Weighted Mean

Summation (Weight x Data) / Summation(Weight)

How do you find the Range?

Xmax - Xmin

How do you find the sample mean?

Summation(X) / n

How do you find the sample standard deviation?

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Computational Formula (Standard Deviation)

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Population Standard Deviation

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Sample Variance

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Population Variance

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Sample Mean for Grouped Data

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